STE ink staining Kiwo Multi-Tex... Anybody experience this?

[mikezincali]

Hi All,

I've been tired for the last few months, too many 12+ hour days... So I hope this makes sense. I've been reading thread after thread for hours tonight, and I've learned a lot but decided to post this.

I'm the lead screen tech (the only screen tech) at a company here in California, I'm exposing 200 screens per day on average. 150 on a "slow" day, 300 on a busy day. I use an STE II, a Uni-Kote, and a 6k Tri-light for film jobs/cap exposures. I've been using Murakami T9 almost exclusively, and I love it, minus the occasional stuck film. The stickiness hasn't bothered me, as I usually knock out all the film jobs in the AM while I'm shooting the 12-14 color jobs on STE, which means I'm using screens from the previous day which the films don't stick too.

My boss, on a whim, decides he wants to switch to Kiwo muti-tex red to save $80/month, during the busiest month of the year (12, 15, 18 hour days, 1 day weekends).

I have no problems with Kiwo, I used one-coat for years at a smaller shop, but this multi-tex is giving me issues. First, the STE ink soaks in/stains the emulsion, it gives solid images/letters a weird drop shadow, and half-tone images are grey and harder to see when I'm washing out. I do use a post expose dip tank, but the screens only go in the drink for a moment before they hit the sink for washout. This happens even if I expose for too long. Second problem, I'm losing detail coming out of the STE and it's driving me nuts. (I should note, I've had great results with the multi-tex on the 6k Tri-Light) I've under exposed, over exposed, and I'm just not getting the finer half-tones. I coat 1/1, rounded edge, with the uni-kote on the fastest setting. 225-48 is the mesh I use the most, with 200-48 coming in 2nd. Does viscosity have something to do with this? Am I dealing with LED light refraction because of less EOM? The multi-tex is rated at 10,000 mPas, T9 is 17,000... Which makes me wonder if I need to try 2/2, or 1/1 at a slower speed. If that's the case, the multi-tex just isn't an option for me, when I can use the T9 all day coating 1/1 at top speed, retain all the details, and deal with no weird stains or drop shadows from the STE ink. Honestly the level of detail I was getting with the STE/T9 was astounding, coming from a small shop that was film only.

Anything at all that adds an extra step, or adds any time to my process isn't an option for me, but I really want to figure this out... Any advice will be greatly appreciated!

I should note that I do not have an EOM meter, or a moisture meter, or a humidity sensor... Yet. The room is climate controlled though, and has an absurdly large exhaust fan.



One thing I definitely learned... If your room is dialed, don't let anybody change anything during the busiest month of the year.

Sorry for the long (first) post, happy holidays

[BrazosDesigns]

FWIW....

I have been using Kiwo Multi Tex Red for a year and a half with plastisol with good results (once I got it really dialed in).  Then I started using water base and the emulsion stained like crazy.   Excessive staining that couldn't be cleaned....

I just received some PHU (Cryocoat) and will be trying that out.  Sometimes the hassle of saving a buck ends up costing you headaches and a lot more money.

[Colin]

Sounds like:  not only was it not broken, but it was working really well.  Tell your boss that all your down time is eating up your production time and causing issues.  Issues = money wasted in the screen room, production, and reclaim.

You have cataloged them all really well, now go to him and show him the issues that will go away if you go back to a better emulsion.

Fyi, I use T9 here with an STE and Starlight.  I add the diazo for its anti halation properties (keeps even the smallest details open/less prone to light wrap).  The detail is phenomenal as well as the water resistance.

[mikezincali]

Brazos, what were you exposing with? MH or LED?

Colin, what affect does the diazo have on your exposure time? Does it impact your reclaim process at all? I tend to shoot a lot of detailed images, and I'm on a constant quest to improve image quality. Which is part of my frustration with the multi-tex, I feel I've taken a step backwards.

My boss is on vacation. We set aside a day in January to coat some brand new screens with both emulsions, to do some tests. In the interim, I'm trying to learn as much as possible. Our lead printer says he used multi-tex some years ago with no issue, but he was only using MH to expose. Neither he or my boss are really aware of the differences between MH/LED, and I'm just learning about them myself. Started when I printed an image on a 400m cap screen, but exposed it on the 6k tri-light with the vacuum off and I got a much higher quality stencil.

Fascinating stuff, just hate going through all these issues when I'm slammed.

[Colin]

I dont know enough about high density and led.  But I like the thought of a powerful multi spectrum bulb on high density emulsion.

As I understand it:  A 5k bulb is about equal to M&R's starlight led exposure system.

With that said:  I coat with a monster max scoop coater that only has a sharp edge, but will still lay down some good emulsion.  On my 150s mesh (we only use thin thread here) I coat 1/2 and my screen have a "good" stencil  It has been measured between 30%-50% eom.  My exposure times are about 30 seconds with the addition of the diazo.  My 180s I coat 1/1 with exposure times at about 20 seconds.  225s = 12 seconds, 270 = 7 seconds,  330 = 6 seconds.

I like to overexpose my stencils, so my burn times on 150s is between 40-50 seconds and my 180s is about 30 seconds.

The exposure times, even up to one minute is fine for our work flow.  We run best detail on our iImage, so things are slow enough to allow long burn times (and we do not go through as many screens as you do).

On my 225s mesh I can hold 60 lpi down to the 2% dot the iImage gives me.  65 lpi starts to get wonky below 10% ish, I just need to make sure my stencil is not to thick and that I soak my screen longer before rinsing out the detail.  Honestly, 60 lpi is more than fine for our customers, so we dont push that envelope very much.

We used Saati PHU (also known as Cryocoat from Ryonet) in the beginning and it was waaaaay to fast to dial in properly.  I knew the T9 was similar, so I wanted to slow it down with the diazo and knowing that I would then increase my detail resolution was a wonderful bonus.  The addition of the diazo is meant just to make sure that there is as close to zero light undercutting my fine details as possible.  It also helps with the water resistance because of the longer exposure (I have been told).

Your cap film is probably not dialed in for the narrow light spectrum of LED.  The 6k unit has a multispectrum bulb which is probably giving you a full solid exposure. 

Also, make sure your screen are properly dry/moisture around 35%   This will give your screens the best chance to rinse out properly.

Have have read about other shops complaining about resolution issues with multi tex.  Most of them have purchased on price....  You do get what you pay for.

Hope my rambles have helped

[Colin]

Just read your post about HD on Noortrd post.

Do you have the exposure unit attached to the iImage or a free standing Starlight led unit?

[mikezincali]

It's attached. I use the rear exposure, not the front scanning one. 250-260 seconds seems to work for 400m, but if I print the image on the STE with exposure off, and expose on the tri-lock (also 250-260 sec, vacuum off) I seem to get a cleaner washout, with cleaner edges. I still struggle with certain images, when things slow down I'll have time to dial things in more.

[mikezincali]

Thanks for the info. Definitely going to read again when I'm able. I also use thin thread, lots of 150/200/225/310. Might give 180 a shot, don't have any of those. Got to run, thanks again!

[Colin]

since exposure times will be very similar....

Would it be smarter for you to just use the tri-light for your exposures and use the STE for imaging your screens?  Your throughput should increase and detail will still be amazing.

What resolution do you run your print heads at?

When you get a chance, read through posts made by Murakami's Rep ABuffington.

He gives some great in depth knowledge about light spectrums and how there are different resins that need specific light frequencies, and output info from various light sources.  You can also look up stuff on youtube they have posted.

At the end of the day, it sounds like you have a handle on what works.  Now lets expand your understanding of why it works

[mikezincali]

That's why I'm here, for the knowledge. Not only do I want to expand my understanding for myself, I need to be able to articulate clearly why and how some things work and others do not. I love what I do, and take my job seriously. I took over the screen room middle of September, and we've been slammed ever since. I have a lot to learn, and I have a list of improvements/changes I will be making over the next year. Luckily about to enter a "slow" period (150-175 screens/day).

I'll double check Tuesday, but I believe we're printing 1200:900 resolution, 2 heads, using 12 pass on "high". I was told to always use high, and been to busy to try anything else...

I have thought about imaging on STE, exposing on the Tri-Light. I wonder, though... The extra electricity may cancel out the money saved on the multi-tex 

If I told my boss that's what I need to do, he'll probably be ok with switching back to T9.

Going to do some testing this week if I have time. Our tech is on vacation so I get to deal with all DTG troubleshooting/repairs... But that's a whole different topic I'll avoid for the moment 

Again, thank you for the info.

[Dottonedan]

If we are talking about the same things, the staining only happens (after the exposure no matter the exposure type) or duration.  I've seen screens for hours to come back and wash out and no stain issues. I think it's all in how you handle the wash out process.

1st and foremost, If staining, its temporary (or should be) and comes out in the reclaim. Then, the trick to getting it to not stain, is to wash off about 90% of the ink excess right away, then, start your true washout. 
Meaning, before you sail, blow off the majority of the ink. Then soak, or let it sit in the booth for a few seconds or a minute and wash out.

We have an automatic washer and the don't get a chance to soften or soak. We have no stains tho...or at least what I would call stains. There is some residual colorization but it's meaningless to mention. No staining (that I am aware of) actually causes any effect on the print result itself and when I've seen the staining, it does not stay there. (Comes out clean from reclaim).

[mikezincali]

Dan,

It is temporary, and does come out in reclaim. It's more annoying than anything, and makes me scratch my head, as I don't have the issue with other emulsions (T9/SP1400).

I'll snap a couple of photos today, I'll have to post them later though. I'm off to races, have to pump a bunch of screens out so I can go deal with a couple of down DTG's.

[ZooCity]

I second going to the MH for all expos.  You'll probably go faster since the i image will only be imaging. 

From my experience I would say a starlight's array is maybe an upgrad from a 1k MH maybe but a clear downgrade from a 5k or higher. 

The bigger issue is that the CTS masking won't image the new emulsion optimally.  I would get on the horn with M&R regarding that, I'm sure they've bumped into users using all possible emulsions at this point. 

Funny what some will do to "save" 80 bucks a month huh?  Hang in there and hope the higher ups listen a little regarding the true cost of that cheaper emulsion.

[Dottonedan]

Dan,

It is temporary, and does come out in reclaim. It's more annoying than anything, and makes me scratch my head, as I don't have the issue with other emulsions (T9/SP1400).

I'll snap a couple of photos today, I'll have to post them later though. I'm off to races, have to pump a bunch of screens out so I can go deal with a couple of down DTG's.

Then I'd be sure to blow off the excess ink right away before washing out the image. That does take away most of any issues with visual staining. Again, while you may feel it's bothersome, it does not affect the print.

I'll poke Zoo in the rib a little and say that I don't believe the 5k will be around long. My guess is that they will go away within 5 years like The Imagesetters. Too much out there that makes a 5k not that beneficial when weighing it against the lamp replacement. Zoo thinks I'm full of it but time will tell.

[ZooCity]

Dan,

It is temporary, and does come out in reclaim. It's more annoying than anything, and makes me scratch my head, as I don't have the issue with other emulsions (T9/SP1400).

I'll snap a couple of photos today, I'll have to post them later though. I'm off to races, have to pump a bunch of screens out so I can go deal with a couple of down DTG's.

Then I'd be sure to blow off the excess ink right away before washing out the image. That does take away most of any issues with visual staining. Again, while you may feel it's bothersome, it does not affect the print.

I'll poke Zoo in the rib a little and say that I don't believe the 5k will be around long. My guess is that they will go away within 5 years like The Imagesetters. Too much out there that makes a 5k not that beneficial when weighing it against the lamp replacement. Zoo thinks I'm full of it but time will tell.

Oh I agree and I hope it's sooner than that!  Purpose built LEDs would be a good start.   There's a reason people find superior results with MH in a side by side right now.